This invention relates generally to power door drive equipment for mass transit vehicles, and more particularly to door operators for use in vehicles requiring essentially uninterrupted side wall surfaces when the vehicular doors are closed. Operators of this type are commonly used to operate "plug" doors in that in a closed position, the doors occupy space essentially equal to that of the car wall were it not interrupted by a door opening. In a door open position, doors of this type move away from the opening outside of the vehicle after being "unplugged."
Known operators providing plugging and unplugging operation along with outside location of open door leaves are typified by U.S. Pat. No. 5,142,823. While these units appear satisfactory, the structures utilized incorporate certain shortcomings, particularly in properly handling the large cantilever load having a substantial inertial component imposed on the operator structure by the doors typically used. Also, if tracked guides into and out of the car wall opening are used, inertial wear on track members reduces door reliability. When rotary prime movers are required, conversion to rectilinear motion involves complicated mechanisms, including rotating screw and nut components. Also, the above-mentioned system utilizes mechanical belts or cables which, in many cases, also cannot be used.
In particular, the invention disclosed herein utilizes a rotary prime mover, mechanical drives excluding cables and belts. Further, the plugging and unplugging operation disclosed involves relatively simple mechanical linkages of the type having high reliability and requiring low maintenance.
Therefore, it is an object of this invention to provide a highly reliable outside sliding plug door system driven by a rotary electrical or fluid powered motor.
It is a further object of this invention to provide an outside sliding plug door drive in which the plugging and unplugging operation is actuated by simple and inexpensive mechanical linkages.
It is a further object of this invention to provide an outside sliding plug door drive wherein the plug/unplug operation, and sliding door movement outside the car body is provided by a single rotary actuator.
It is an additional object of this invention to provide an outside sliding plug door operator wherein in a door closed position the individual door panel hangers are maintained within the confines of the opening in the car side wall.
It is a further object of this invention to provide an outside sliding plug door operator wherein door weight loads and door drive loads are applied to separate components.
It is an additional object of the invention to provide an outside sliding plug door operator wherein door sliding and plugging movements are accomplished by separate mechanical components activated sequentially through response to drive motor torque.